ABSTRACT Australia was isolated for approximately 40 million years from the presence of eutherian predation until the introduction of the dingo (Canis familiaris; 4000 years ago), foxes (Vulpes vulpes; 1871) and feral cats (Felis catus; post-1788). The arrival of these invasive species coincides with the decline and extinction of many native mammals, specifically within the critical weight range (35–5500 g). These extinctions are likely a result of competition and predation, where locomotor performance and the associated behaviours contribute largely to overall fitness. We used the population responses of native fauna in the presence of introduced predators to establish a research framework. Introduction/extinction timelines, predator diets, and prey occurrence were used to identify invasive/native relationships where predation may define the population outcome. We then examined the locomotor performance of these species using current data (maximum speeds). Consumption of prey items does not seem to be associated with the probability of the predator encountering the prey. Dingoes had the most variable mammalian prey of all invasive predators, likely due to higher maximal speeds. Feral cats favour Dasyuridae and smaller species, preying upon these prey groups more than dingoes and foxes. The role of locomotor performance in invasive ecology is not well understood; we identified relationships for further exploration.
{"title":"Classifying relationships that define interactions between native and invasive species in Australian ecosystems","authors":"Joshua L. Gaschk, C. Clemente","doi":"10.1071/ZO22011","DOIUrl":"https://doi.org/10.1071/ZO22011","url":null,"abstract":"ABSTRACT Australia was isolated for approximately 40 million years from the presence of eutherian predation until the introduction of the dingo (Canis familiaris; 4000 years ago), foxes (Vulpes vulpes; 1871) and feral cats (Felis catus; post-1788). The arrival of these invasive species coincides with the decline and extinction of many native mammals, specifically within the critical weight range (35–5500 g). These extinctions are likely a result of competition and predation, where locomotor performance and the associated behaviours contribute largely to overall fitness. We used the population responses of native fauna in the presence of introduced predators to establish a research framework. Introduction/extinction timelines, predator diets, and prey occurrence were used to identify invasive/native relationships where predation may define the population outcome. We then examined the locomotor performance of these species using current data (maximum speeds). Consumption of prey items does not seem to be associated with the probability of the predator encountering the prey. Dingoes had the most variable mammalian prey of all invasive predators, likely due to higher maximal speeds. Feral cats favour Dasyuridae and smaller species, preying upon these prey groups more than dingoes and foxes. The role of locomotor performance in invasive ecology is not well understood; we identified relationships for further exploration.","PeriodicalId":55420,"journal":{"name":"Australian Journal of Zoology","volume":"64 1","pages":"22 - 35"},"PeriodicalIF":0.8,"publicationDate":"2022-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85295739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Across Australia’s monsoon tropics and vast arid zone isolated regions or ‘islands’ of upland or rocky habitat are home to disjunct populations of many taxa of plants and animals. Comparative analyses of lineages that occur across these habitat islands provide opportunities to understand when and how environmental change drove isolation and diversification across arid Australia. Here we present an analysis of mitochondrial genetic diversity across disjunct populations of geckos in the Nephrurus asper group. Dating analyses suggest that disjunct and genetically divergent populations spanning the northern half of Australia diverged through the Plio–Pleistocene. Based on the timing of divergence and current habitat associations we hypothesise that species in this lineage were isolated by the expansion of unsuitable arid-zone habitats from the late Pliocene onwards. Across most areas, these barriers appear to be sandy or stony deserts. However, in eastern Australia genetically divergent populations are separated by grassland on flat vertisol-dominated soils (‘blacksoils’), suggesting that these habitats also expanded during the late Pliocene aridification. Finally, we show that western Queensland populations formerly referred to N. asper are genetically divergent and diagnosable on the basis of colour pattern and, herein, recognise these populations as a distinct species.
{"title":"Plio–Pleistocene vicariance across arid Australia in the ‘Spiny Knob-tailed Geckos’ (Nephrurus asper group), with the description of a new species from western Queensland","authors":"P. Oliver, S. Donnellan, Bee F. Gunn","doi":"10.1071/ZO22008","DOIUrl":"https://doi.org/10.1071/ZO22008","url":null,"abstract":"ABSTRACT Across Australia’s monsoon tropics and vast arid zone isolated regions or ‘islands’ of upland or rocky habitat are home to disjunct populations of many taxa of plants and animals. Comparative analyses of lineages that occur across these habitat islands provide opportunities to understand when and how environmental change drove isolation and diversification across arid Australia. Here we present an analysis of mitochondrial genetic diversity across disjunct populations of geckos in the Nephrurus asper group. Dating analyses suggest that disjunct and genetically divergent populations spanning the northern half of Australia diverged through the Plio–Pleistocene. Based on the timing of divergence and current habitat associations we hypothesise that species in this lineage were isolated by the expansion of unsuitable arid-zone habitats from the late Pliocene onwards. Across most areas, these barriers appear to be sandy or stony deserts. However, in eastern Australia genetically divergent populations are separated by grassland on flat vertisol-dominated soils (‘blacksoils’), suggesting that these habitats also expanded during the late Pliocene aridification. Finally, we show that western Queensland populations formerly referred to N. asper are genetically divergent and diagnosable on the basis of colour pattern and, herein, recognise these populations as a distinct species.","PeriodicalId":55420,"journal":{"name":"Australian Journal of Zoology","volume":"55 1","pages":"216 - 228"},"PeriodicalIF":0.8,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90832422","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kimberly Maute, Paul G. Story, G. Hose, A. Warden, G. Dojchinov, K. French
ABSTRACT The use of chemical pesticides to manage locust populations in natural ecosystems is likely to impact non-target arthropods and their predators. However, the relative effects of different locust control applications on Australian birds are unknown. Aerial applications of fipronil and fenitrothion are examples of two pesticides used in locust control in semiarid Australia. To test the relative impacts of pesticides on non-target fauna, pesticides were applied to replicate sites using aerial ultra-low-volume application methods. The body condition and biomarkers of pesticide exposure in resident white-winged fairy wrens (Malurus leucopterus leuconotus) at treatment and control sites were measured for two weeks before and after treatments. No measures suggested negative impacts of pesticide applications. However, birds monitored at treatment sites gained mass, possibly due to indirect impacts of pesticides on bird feeding patterns or the availability or behaviour of insect prey. Bird mass measures remained high at fipronil sites, whereas the mass of birds at fenitrothion sites returned to baseline levels within one week. As this study was conducted during dry conditions, when locust plagues are less likely, future insecticide research should also consider the availability of insect prey, its effect on insectivore feeding behaviour and the interaction of rainfall events.
{"title":"Observations on populations of a small insectivorous bird, Malurus leucopterus leuconotus Dumont, after an application of two ultra-low-volume (ULV) insecticides, fenitrothion and fipronil, in arid Australia","authors":"Kimberly Maute, Paul G. Story, G. Hose, A. Warden, G. Dojchinov, K. French","doi":"10.1071/ZO22006","DOIUrl":"https://doi.org/10.1071/ZO22006","url":null,"abstract":"ABSTRACT The use of chemical pesticides to manage locust populations in natural ecosystems is likely to impact non-target arthropods and their predators. However, the relative effects of different locust control applications on Australian birds are unknown. Aerial applications of fipronil and fenitrothion are examples of two pesticides used in locust control in semiarid Australia. To test the relative impacts of pesticides on non-target fauna, pesticides were applied to replicate sites using aerial ultra-low-volume application methods. The body condition and biomarkers of pesticide exposure in resident white-winged fairy wrens (Malurus leucopterus leuconotus) at treatment and control sites were measured for two weeks before and after treatments. No measures suggested negative impacts of pesticide applications. However, birds monitored at treatment sites gained mass, possibly due to indirect impacts of pesticides on bird feeding patterns or the availability or behaviour of insect prey. Bird mass measures remained high at fipronil sites, whereas the mass of birds at fenitrothion sites returned to baseline levels within one week. As this study was conducted during dry conditions, when locust plagues are less likely, future insecticide research should also consider the availability of insect prey, its effect on insectivore feeding behaviour and the interaction of rainfall events.","PeriodicalId":55420,"journal":{"name":"Australian Journal of Zoology","volume":"1 1","pages":"229 - 238"},"PeriodicalIF":0.8,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72684610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
ABSTRACT Several types of bone development are present in the Australian lungfish, Neoceratodus forsteri, the only extant member of the family Neoceratodontidae. In this species, dermal and parachondral bones form around the chondrocranium and mandible, to protect the brain and sense organs, to support the dentition and to facilitate oral function. The notochord persists throughout life. The quadrate and Meckel’s cartilage remain cartilaginous, as does the chondrocranium. Anterior elements of the hyoid arch, the basihyal and hypohyals, do not ossify. The ceratohyal, which articulates with the hypohyals, ossifies perichondrally, as do the exoccipital bone and the ribs of the trunk, including the cranial rib. The exoccipital bone is embedded in the chondrocranium in the adult fish, and the cranial rib is immobile. Some elements of the skeleton, such as the pectoral and pelvic fins, and the pelvic girdle, remain cartilaginous, and the skeletal elements in these fins resemble the structure of the tail. Fully developed bone is trabecular or lamellar, and does not include vascular elements. Endochondral ossification does not occur in the living Australian lungfish.
{"title":"Osteogenesis in the Australian lungfish, Neoceratodus forsteri (Osteichthyes: Dipnoi)","authors":"A. Kemp","doi":"10.1071/ZO22004","DOIUrl":"https://doi.org/10.1071/ZO22004","url":null,"abstract":"ABSTRACT Several types of bone development are present in the Australian lungfish, Neoceratodus forsteri, the only extant member of the family Neoceratodontidae. In this species, dermal and parachondral bones form around the chondrocranium and mandible, to protect the brain and sense organs, to support the dentition and to facilitate oral function. The notochord persists throughout life. The quadrate and Meckel’s cartilage remain cartilaginous, as does the chondrocranium. Anterior elements of the hyoid arch, the basihyal and hypohyals, do not ossify. The ceratohyal, which articulates with the hypohyals, ossifies perichondrally, as do the exoccipital bone and the ribs of the trunk, including the cranial rib. The exoccipital bone is embedded in the chondrocranium in the adult fish, and the cranial rib is immobile. Some elements of the skeleton, such as the pectoral and pelvic fins, and the pelvic girdle, remain cartilaginous, and the skeletal elements in these fins resemble the structure of the tail. Fully developed bone is trabecular or lamellar, and does not include vascular elements. Endochondral ossification does not occur in the living Australian lungfish.","PeriodicalId":55420,"journal":{"name":"Australian Journal of Zoology","volume":"29 1","pages":"205 - 215"},"PeriodicalIF":0.8,"publicationDate":"2022-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83101580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Dundas, Lara Osborne, A. Hopkins, K. Ruthrof, P. Fleming
ABSTRACT Bioturbation by digging animals is important for key forest ecosystem processes such as soil turnover, decomposition, nutrient cycling, water infiltration, seedling recruitment, and fungal dispersal. Despite their widespread geographic range, little is known about the role of the short-beaked echidna (Tachyglossus aculeatus) in forest ecosystems. We measured the density and size of echidna diggings in the Northern Jarrah Forest, south-western Australia, to quantify the contribution echidna make to soil turnover. We recorded an overall density of 298 echidna diggings per hectare, 21% of which were estimated to be less than 1 month old. The average size of digs was 50 ± 25 mm in depth and 160 ± 61 mm in length. After taking into account seasonal digging rates, we estimated that echidnas turn over 1.23 tonnes of soil ha−1 year−1 in this forest, representing an important role in ecosystem dynamics. Our work contributes to the growing body of evidence quantifying the role of these digging animals as critical ecosystem engineers. Given that the echidna is the only Australian digging mammal not severely impacted by population decline or range reduction, its functional contribution to health and resilience of forest ecosystems is increasingly important due to the functional loss of most Australian digging mammals.
{"title":"Bioturbation by echidna (Tachyglossus aculeatus) in a forest habitat, south-western Australia","authors":"S. Dundas, Lara Osborne, A. Hopkins, K. Ruthrof, P. Fleming","doi":"10.1071/ZO22019","DOIUrl":"https://doi.org/10.1071/ZO22019","url":null,"abstract":"ABSTRACT Bioturbation by digging animals is important for key forest ecosystem processes such as soil turnover, decomposition, nutrient cycling, water infiltration, seedling recruitment, and fungal dispersal. Despite their widespread geographic range, little is known about the role of the short-beaked echidna (Tachyglossus aculeatus) in forest ecosystems. We measured the density and size of echidna diggings in the Northern Jarrah Forest, south-western Australia, to quantify the contribution echidna make to soil turnover. We recorded an overall density of 298 echidna diggings per hectare, 21% of which were estimated to be less than 1 month old. The average size of digs was 50 ± 25 mm in depth and 160 ± 61 mm in length. After taking into account seasonal digging rates, we estimated that echidnas turn over 1.23 tonnes of soil ha−1 year−1 in this forest, representing an important role in ecosystem dynamics. Our work contributes to the growing body of evidence quantifying the role of these digging animals as critical ecosystem engineers. Given that the echidna is the only Australian digging mammal not severely impacted by population decline or range reduction, its functional contribution to health and resilience of forest ecosystems is increasingly important due to the functional loss of most Australian digging mammals.","PeriodicalId":55420,"journal":{"name":"Australian Journal of Zoology","volume":"14 1","pages":"197 - 204"},"PeriodicalIF":0.8,"publicationDate":"2022-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78658386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kirilee Chaplin, Katie L. Smith Date, R. Bray, K. Miller, Maiko L. Lutz, Emma Razeng, M. Thompson, D. G. Chapple
ABSTRACT Human-mediated dispersal of animals often acts to bring populations that have been separated for substantial periods of evolutionary time (e.g. millions of years) in their native range into contact in their introduced range. Whether these taxa successfully interbreed in the introduced range provides information on the strength of reproductive isolation amongst them. The invasive delicate skink (Lampropholis delicata) has been accidentally introduced to Lord Howe Island from four genetically divergent (>2 million years) regions of the species’ native range in eastern Australia. We used mitochondrial DNA and microsatellite data to investigate whether the individuals from four of the native-range source regions are interbreeding on Lord Howe Island. Our analyses indicate that intraspecific hybridisation among individuals from all four native-range source regions is occurring. Although there is little evidence for hybrids in the northern end of Lord Howe Island (proportion of hybrids: 0–0.02; n = 31), there is a high proportion of hybrids in the central (0.33–0.69; n = 59) and southern regions (0.38–0.75; n = 8) of the island. Given the strong evidence for interbreeding among all four native-range source regions examined, and the relatively minor morphological, life-history and phenotypic variation among them, we suggest that the delicate skink should continue to be treated as a single, widespread, but variable species.
{"title":"Intraspecific hybridisation of an invasive lizard on Lord Howe Island","authors":"Kirilee Chaplin, Katie L. Smith Date, R. Bray, K. Miller, Maiko L. Lutz, Emma Razeng, M. Thompson, D. G. Chapple","doi":"10.1071/ZO21045","DOIUrl":"https://doi.org/10.1071/ZO21045","url":null,"abstract":"ABSTRACT Human-mediated dispersal of animals often acts to bring populations that have been separated for substantial periods of evolutionary time (e.g. millions of years) in their native range into contact in their introduced range. Whether these taxa successfully interbreed in the introduced range provides information on the strength of reproductive isolation amongst them. The invasive delicate skink (Lampropholis delicata) has been accidentally introduced to Lord Howe Island from four genetically divergent (>2 million years) regions of the species’ native range in eastern Australia. We used mitochondrial DNA and microsatellite data to investigate whether the individuals from four of the native-range source regions are interbreeding on Lord Howe Island. Our analyses indicate that intraspecific hybridisation among individuals from all four native-range source regions is occurring. Although there is little evidence for hybrids in the northern end of Lord Howe Island (proportion of hybrids: 0–0.02; n = 31), there is a high proportion of hybrids in the central (0.33–0.69; n = 59) and southern regions (0.38–0.75; n = 8) of the island. Given the strong evidence for interbreeding among all four native-range source regions examined, and the relatively minor morphological, life-history and phenotypic variation among them, we suggest that the delicate skink should continue to be treated as a single, widespread, but variable species.","PeriodicalId":55420,"journal":{"name":"Australian Journal of Zoology","volume":"20 1","pages":"184 - 196"},"PeriodicalIF":0.8,"publicationDate":"2022-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90978644","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. McKay, J. Hufschmid, A. Meredith, Patsy A. Zendejas-Heredia, K. Moseby
ABSTRACT Toxoplasma gondii is a ubiquitous protozoan transmitted by felids and infection, morbidity, and mortality occur in numerous marsupial species. This study explores the relationship between cat exposure and Toxoplasma in burrowing bettongs (Bettongia lesueur) in the Arid Recovery Reserve (ARR), South Australia. We estimated seroprevalence, using a modified agglutination test for T. gondii-specific immunoglobulins, in cat-free and cat-exposed bettong populations. Tissue samples collected opportunistically from bettong carcasses and from cats within and around the reserve were screened for T. gondii DNA using multiplex real-time polymerase chain reaction (M-qPCR). Two cats trapped inside the ARR tested positive (50.0%; 95% CI: 15.0–85.0%). All bettongs tested from the cat-free (n = 48) and cat-exposed (n = 19) exclosures were seronegative (95% CI: 0–7.41% and 0–16.82% respectively). We found no evidence of fatal toxoplasmosis, with all bettong carcasses negative on M-qPCR (n = 11). We propose that T. gondii was not detected in bettongs coexisting with cats primarily due to low exposure of bettongs at the time of sampling, possibly due to poor oocyst viability in arid conditions or low shedding by cats. Ongoing screening throughout high and low rainfall years should be conducted to better establish the risk of Toxoplasma to bettongs in the ARR.
{"title":"Seroprevalence of Toxoplasma gondii in burrowing bettongs (Bettongia lesueur): a comparison of cat-free and cat-exposed populations","authors":"P. McKay, J. Hufschmid, A. Meredith, Patsy A. Zendejas-Heredia, K. Moseby","doi":"10.1071/ZO22010","DOIUrl":"https://doi.org/10.1071/ZO22010","url":null,"abstract":"ABSTRACT Toxoplasma gondii is a ubiquitous protozoan transmitted by felids and infection, morbidity, and mortality occur in numerous marsupial species. This study explores the relationship between cat exposure and Toxoplasma in burrowing bettongs (Bettongia lesueur) in the Arid Recovery Reserve (ARR), South Australia. We estimated seroprevalence, using a modified agglutination test for T. gondii-specific immunoglobulins, in cat-free and cat-exposed bettong populations. Tissue samples collected opportunistically from bettong carcasses and from cats within and around the reserve were screened for T. gondii DNA using multiplex real-time polymerase chain reaction (M-qPCR). Two cats trapped inside the ARR tested positive (50.0%; 95% CI: 15.0–85.0%). All bettongs tested from the cat-free (n = 48) and cat-exposed (n = 19) exclosures were seronegative (95% CI: 0–7.41% and 0–16.82% respectively). We found no evidence of fatal toxoplasmosis, with all bettong carcasses negative on M-qPCR (n = 11). We propose that T. gondii was not detected in bettongs coexisting with cats primarily due to low exposure of bettongs at the time of sampling, possibly due to poor oocyst viability in arid conditions or low shedding by cats. Ongoing screening throughout high and low rainfall years should be conducted to better establish the risk of Toxoplasma to bettongs in the ARR.","PeriodicalId":55420,"journal":{"name":"Australian Journal of Zoology","volume":"192 1","pages":"175 - 183"},"PeriodicalIF":0.8,"publicationDate":"2022-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85006540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jessica L. Williams, D. Harley, D. Watchorn, L. McBurney, D. Lindenmayer
ABSTRACT The body size of mammals is influenced by several evolutionary, morphological, physiological and ecological factors. Studies of body size can provide insight into the processes underlying observed variation in patterns of mammal morphology. We sought to determine if body weight in Leadbeater’s possum (Gymnobelideus leadbeateri) is related to environmental variables and/or sex. Using linear regression modelling, we quantified the influence on body weight of broadscale geographic variables such as latitude and elevation, site-level indicators of forest productivity (forest type, slope, aspect and topographic wetness) and an individual-level variable (sex). We found that body weight was significantly associated with elevation and sex, with individuals being heavier at higher elevations and males (on average) being heavier than females. Monitoring body weight changes over time within particular forest types will be valuable, given the variations in temperature and resource productivity throughout the range of Leadbeater’s possum that are likely to arise from climate change.
{"title":"Relationship between body weight and elevation in Leadbeater’s possum (Gymnobelideus leadbeateri)","authors":"Jessica L. Williams, D. Harley, D. Watchorn, L. McBurney, D. Lindenmayer","doi":"10.1071/ZO21042","DOIUrl":"https://doi.org/10.1071/ZO21042","url":null,"abstract":"ABSTRACT The body size of mammals is influenced by several evolutionary, morphological, physiological and ecological factors. Studies of body size can provide insight into the processes underlying observed variation in patterns of mammal morphology. We sought to determine if body weight in Leadbeater’s possum (Gymnobelideus leadbeateri) is related to environmental variables and/or sex. Using linear regression modelling, we quantified the influence on body weight of broadscale geographic variables such as latitude and elevation, site-level indicators of forest productivity (forest type, slope, aspect and topographic wetness) and an individual-level variable (sex). We found that body weight was significantly associated with elevation and sex, with individuals being heavier at higher elevations and males (on average) being heavier than females. Monitoring body weight changes over time within particular forest types will be valuable, given the variations in temperature and resource productivity throughout the range of Leadbeater’s possum that are likely to arise from climate change.","PeriodicalId":55420,"journal":{"name":"Australian Journal of Zoology","volume":"81 1","pages":"167 - 174"},"PeriodicalIF":0.8,"publicationDate":"2022-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76717770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Abstract. Senescence is a decline in reproduction and survival rate with advancing age resulting from deterioration of somatic tissues and systems throughout the body. Age-related somatic changes (somatic ageing) have been studied extensively in vertebrates but are less well known in other animals, including insects. Since adult insects have very limited ability to repair their exoskeleton, somatic ageing could involve deterioration and discolouration of the cuticle. We investigated age-related changes in wing pigmentation and abdominal cuticle necrosis in females of the Australian leaf insect Phyllium monteithi. Adult females varied markedly in the extent and pattern of pigmentation on their bodies, and we found that pigment spots on the forewings increased in size with age in most individuals. As females aged, most individuals also exhibited increasing levels of abdominal cuticle necrosis, resulting in the loss of abdominal cuticle along the margin of the abdomen. Neither the extent of pigmentation nor cuticle loss were clearly associated with reduced fecundity or longevity in the protected laboratory environment, but it remains unknown whether these age-related changes have functional implications in the wild. Our results show that the P. monteithi exoskeleton undergoes complex changes with age, with potential implications for functional traits and fitness.
{"title":"Exoskeleton ageing and its relation to longevity and fecundity in female Australian leaf insects (Phyllium monteithi)","authors":"R. Bonduriansky, Caitlin Creak","doi":"10.1071/ZO21052","DOIUrl":"https://doi.org/10.1071/ZO21052","url":null,"abstract":"Abstract. Senescence is a decline in reproduction and survival rate with advancing age resulting from deterioration of somatic tissues and systems throughout the body. Age-related somatic changes (somatic ageing) have been studied extensively in vertebrates but are less well known in other animals, including insects. Since adult insects have very limited ability to repair their exoskeleton, somatic ageing could involve deterioration and discolouration of the cuticle. We investigated age-related changes in wing pigmentation and abdominal cuticle necrosis in females of the Australian leaf insect Phyllium monteithi. Adult females varied markedly in the extent and pattern of pigmentation on their bodies, and we found that pigment spots on the forewings increased in size with age in most individuals. As females aged, most individuals also exhibited increasing levels of abdominal cuticle necrosis, resulting in the loss of abdominal cuticle along the margin of the abdomen. Neither the extent of pigmentation nor cuticle loss were clearly associated with reduced fecundity or longevity in the protected laboratory environment, but it remains unknown whether these age-related changes have functional implications in the wild. Our results show that the P. monteithi exoskeleton undergoes complex changes with age, with potential implications for functional traits and fitness.","PeriodicalId":55420,"journal":{"name":"Australian Journal of Zoology","volume":"31 1","pages":"158 - 165"},"PeriodicalIF":0.8,"publicationDate":"2022-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90220469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lauren H. Thornton, T. Dick, M. Bennett, C. Clemente
Abstract. Kangaroos and other macropodoids stand out among mammals for their unusual hopping locomotion and body shape. This review examines the scaling of hind- and forelimb bones, and the primary ankle extensor muscles and tendons. We find that the scaling of the musculoskeletal system is sensitive to the phylogenetic context. Tibia length increases with positive allometry among most macropodoids, but negative allometry in eastern grey kangaroos and isometry in red kangaroos. Femur length decreases with stronger negative allometry in eastern grey and red kangaroos than among other macropodoids. Muscle masses scale with negative allometry in western grey kangaroos and with isometry in red kangaroos, compared to positive allometry in other macropodoids. We further summarise the work on the hopping gait, energetics in macropodoids, and stresses in the musculoskeletal system in an evolutionary context, to determine what trade-offs may limit locomotor performance in macropodoids. When large kangaroos hop, they do not increase oxygen consumption with speed, unlike most mammals, including small hopping species. We conclude that there is not enough information to isolate the biomechanical factors that make large kangaroos so energy efficient. We identify key areas for further research to fill these gaps.
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